You only gain full exp from mobs that are above/below you by 5 levels, you may also miss a lot more hits

Stonefalls: Level 1 – 16

Complete the quest from Holgunn at zone one.

Go to the dungeon at zone two. There is also a skyshard located here.

Take the quest at zone three. Complete it and the dungeon. This should give you enough exp to get to level 6, or at least close to it.

Grind at zone four until you reach level 16.

Deshaan: Level 16-23

Grind at zone one until level 23.

Zone two is an alternate option if it’s too crowded. You can also stay here until level 28 but only as a back-up if the next area is also too crowded.

Shadowfen: Level 23-34

Grind at zone one until level 32 all though you can leave at level 28 if you get bored and move to zone 2. You can grind here until 34. It is highly recommended to move to this zone at level 28 because it gives the best exp, however it may be a little crowded.

The Rift: Level34-47

Zone one from level 34 to 36.

Once you’ve hit level 36 move to zone two, if there are too many people you can tag the mobs as there is a high respawn rate.

Cold harbor: Level 47 – 50

We found two spots that are amazing. I personally like Cliffs of Failure (zone two) the most as it’s a bit more hidden and not as heavily farmed.

Zone one is enter-able by the black forge entrance and the mobs you farm are in the first room.
Zone two is enter-able through a portal once inside the cliffs of failure take the second bridge leading up on the right.